Help: COD4 Issues on new system

Hey guys, here is the sys:

q6600 @ 3.1 | GA- p35-D3SL v2.0 | 2.0 GB crucial balstixs ddr 800 | MSI 8800 GT | Seagate Barracuda 500GB 32MB cache | Zalman 9700 cooler.

On the demo version of 3dmark06 I am getting a 14160. However in COD4 it is not smooth at all especially anything to do with lighting. I have the latest drivers for vid card and the BIOs update to 7 on the p35. I cannot figure out why it is "jumpy" and crappy looking both on full settings at 1680 * 1050 and 1280 * 1024. My frame rates fall below 18 - 15.

I had the Gateway FX 7024 which was a Q6600 2.4, 3.0 GB ram, and a 8800GT marked at 13000 and ran COD4 full everything flawlessly. I am confused. I have no idea where to try to find the problem.

Thanks for the help

Dave